UPDATE SEC3_MST a SET SEC3_MST.NAME = 'aaa' WHERE exists(select 1 from SEC4_MST b a.Sec3_Cd = b.SEC4_CD)
改为 UPDATE SEC3_MST SET SEC3_MST.NAME = 'aaa' WHERE SEC3_MST.Sec3_Cd = (select SEC4_MST.SEC4_CD from SEC4_MST,SEC3_MST where SEC4_MST.SEC4_CD=SEC3_MST.SEC3_CD)
UPDATE SEC3_MST SET SEC3_MST.NAME='aaa' WHERE exists(select 1 from SEC4_MST where SEC3_MST.Sec3_Cd = SEC4_MST.SEC4_CD );
UPDATE SEC3_MST SET SEC3_MST.NAME = 'aaa' WHERE SEC3_MST.Sec3_Cd in ( select Sec3_Cd from SEC3_MST,SEC4_MST where SEC3_MST.Sec3_Cd = SEC4_MST.SEC4_CD )
to bzszp(www.bzszp.533.net) exists(select 1 from 这里是什么意思那
各位大虾麻烦留下个联系的方式吧MSN或者qq好以后再请教了。
如果exists后面的select 语句可以检索到数据,就执行update操作。select 1 from ... 跟select * from ...是一样的 不是看返回什么结果,主要是判断有没有结果返回。
exists是什么意思,是包含还是存在?有没有 not exist 这种用法那
有没有 not exist 或者 是 not exists 这种用法那
有not exists的用法 没有exist或not exist
UPDATE SEC3_MST SET SEC3_MST.NAME = 'aaa' where SEC3_MST.Sec3_Cd in(select SEC4_CD from SEC4_MST) 或者 UPDATE SEC3_MST SET SEC3_MST.NAME = 'aaa' where exists (select SEC4_CD from SEC4_MST) exists 如:select id,name from a where exists(select 'X' from b where a.id=b.id) 查出为a表中在b表存在的记录
UPDATE SEC3_MST SET SEC3_MST.NAME = 'aaa' WHERE SEC3_MST.Sec3_Cd = (select SEC4_MST.SEC4_CD from SEC4_MST,SEC3_MST where SEC4_MST.SEC4_CD=SEC3_MST.SEC3_CD)
SET SEC3_MST.NAME='aaa'
WHERE
exists(select 1 from SEC4_MST where SEC3_MST.Sec3_Cd = SEC4_MST.SEC4_CD );
select Sec3_Cd from SEC3_MST,SEC4_MST where SEC3_MST.Sec3_Cd = SEC4_MST.SEC4_CD
)
exists(select 1 from
这里是什么意思那
跟select * from ...是一样的
不是看返回什么结果,主要是判断有没有结果返回。
没有exist或not exist
UPDATE SEC3_MST SET SEC3_MST.NAME = 'aaa' where SEC3_MST.Sec3_Cd in(select SEC4_CD from SEC4_MST)
或者
UPDATE SEC3_MST SET SEC3_MST.NAME = 'aaa' where exists (select SEC4_CD from SEC4_MST)
exists
如:select id,name from a where exists(select 'X' from b where a.id=b.id)
查出为a表中在b表存在的记录